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Winjupos Help

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#1 netwolf

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Posted 15 July 2018 - 11:18 PM

Hi All, 

 

Need some guideance as I have not used Winjupos before. 

 

First

For Mars, Jupiteer and Saturn what is the max time one can use stacks from for best results. 

 

I.e for Mars I have 3 sets of video data

1st one Starts 174110.987 UTC and Ends 174425.987 total ~195secs

2nd one Starts 174427.464 UTC and Ends 174614.876 total ~107secs 

3rd one Starts 175111.125 UTC and Ends 175442.699 total 211.57sec

 

I have more either side but not sure what is the max one can use for best results on the various planets. 

 

Second 

What amount of processin should we do on the stacked frames before running through WinJupos. Assuming we use same process for all. My hope is that by combining I will be able to sharpen more and also get a more detail. I mean should we process as if this will be a final image and then run through winjupos or just do some light sharepening and then rung through winjupos? Or should we derotate without any processing then process the result?

 

 

Appreciate some help and guidance.

 

Kind Regards

Fahim 

 

 



#2 Tom Glenn

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Posted 16 July 2018 - 05:54 PM

There are numerous options to try, and the result will be different each time, so you will have to experiment with your own data.  As for maximum sets to combine for each planet, it's not so much the maximum number, but the total duration in time.  For Jupiter, I take 3 minute videos and can easily combine 20 minute worth of integrations.  For Saturn and Mars, I take 6 minute individual videos, and can combine 30 minutes of data in Winjupos without problem.

 

With regards to processing, I always process each individual video, complete with wavelet sharpening, before combining in Winjupos.  But it is often best to undershapen just slightly, so that you leave room for extra sharpening at the end.  However, I think of Winjupos as more of a noise reduction tool (or an SNR booster, if you prefer), and typically don't do that much sharpening afterwards.  You can easily overdue it if you are expecting to do significant sharpening after combining.  The real question, is whether the derotated images are better or worse than the individual captures.  What you will often find, is that if you take 10 videos of a planet in rapid succession, not all videos give the same quality, because of slight differences in the seeing conditions during each video.  To asses this, you need to process and sharpen them individually.  Usually, out of 10 videos, maybe 3-4 yield a significantly sharper result than the others.  It makes sense to only combine these sharper results in Winjupos.  Otherwise, the derotated image is smoother, but less detailed than the individual captures.  And sometimes, no matter what you do, Winjupos does not give a better result than taking the single best capture and just working on that file.  You never know until you test each set of data.  Obviously, this experimentation can take quite some time, so it's probably only worth doing on nights of really good seeing where the data is worthwhile.  If the results of each individual capture are only average quality, Winjupos isn't going to help much.  

 

There's really no set limit on how many individual images you can combine, but if the total integration period gets very long (more than 30 minutes or so), this can lead to less than optimal results.  But as always, trial and error rules the day. Once you have made measurement files for each image, it is very easy to change the number of images that you combine.  


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#3 RedLionNJ

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Posted 16 July 2018 - 09:25 PM

+1 - in every respect!

 

Really nice summary, Tom.


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#4 Lacaille

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Posted 17 July 2018 - 05:48 PM

Tom, nice summary, but I thought I read somewhere in the past that 10-11 mins or so was about the limit for Jupiter, in terms of total duration that can be integrated by WJ, and had stuck to that limit. I will try some 20 min integrations now to see what happens!

#5 Tom Glenn

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Posted 17 July 2018 - 06:10 PM

It's all trial and error, Mark.  I have no idea what the limit is.  I did integrate 7x3 minutes before, and the result looked OK, although a little less sharp than a shorter integration, but I didn't notice anything weird.  I don't know enough about how the derotation and combination software works to know what exactly happens once you exceed a certain time limit, but I would assume that some weird effects start to happen on the limb.  


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#6 Lacaille

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Posted 17 July 2018 - 07:24 PM

You are right Tom - it is the limb that gives it away.  I just did the test below using a string of 17 images of Jupiter from 23 May 2018 - a night of good seeing with all the individual images consistently good. Each image was derived from 60 secs of video and the interval from the first to the last was about 53 minutes.  I integrated subsets of images to give different overall integration times.

 

It looks like things go well with WJ up to 20 mins of integration. At 25 mins, a limb effect starts to appear; by 43 mins it is quite pronounced, and at 53 mins things look seriously weird across the whole image. But it is the limb that is the main issue beyond 20 mins - the middle of the planet seems to hold its detail OK, albeit perhaps without the resolution of the shorter times.

 

I think it is reassuring that if you had a night where you got some good images over a period of 20-25 mins, but with gaps due to clouds etc, you could still have the option of integrating in WJ to reduce noise. Previous to this thread I would have regarded 11 mins as the upper limit.  It may be that this does not work on all nights but at least it is worth trying. Thanks Fahim for this thread and to Tom for the summary.

 

(Edit - I've just seen at this scale and in jpeg to keep it under the limit it may not be obvious what is going on in the images here so will post to Astrobin as well). 

 

Varying WJ integration times.jpg


Edited by Lacaille, 17 July 2018 - 07:28 PM.

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#7 Tom Glenn

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Posted 17 July 2018 - 07:39 PM

Kudos to you Mark for the nice analysis and figure.  It is nice to see the effects, and although there is no advantage in your example of going beyond 11 minutes in terms of sharpness, it is good to know that longer periods could be tolerated, in case, as you suggest, cloud cover or other technical mishaps require longer gaps in imaging.  


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#8 netwolf

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Posted 19 July 2018 - 10:13 AM

Thanks guys wow Tom that was very detailed, and Mark pictures paint a thousand words and your pics are fantastic. I am trying to do the best I can with a small etx-125 scope that i can, while i do have access to larger scopes I have been inspired by the small bore threads to do more with less. The data i originally posted about did not turn out that good individually so scrapped it. At least i am better armed with time limits and other things to evaluate before using winjupos. Also I thought Saturn max single video should be 2mins or less. Wish Id known to go to 6mins , had "ok" seeing last night but limited myself to 2mins short runs. 

 

I have data and knowledge now to experiment with thanks all. 


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#9 Lacaille

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Posted 19 July 2018 - 05:11 PM

Thanks guys wow Tom that was very detailed, and Mark pictures paint a thousand words and your pics are fantastic. I am trying to do the best I can with a small etx-125 scope that i can, while i do have access to larger scopes I have been inspired by the small bore threads to do more with less. The data i originally posted about did not turn out that good individually so scrapped it. At least i am better armed with time limits and other things to evaluate before using winjupos. Also I thought Saturn max single video should be 2mins or less. Wish Id known to go to 6mins , had "ok" seeing last night but limited myself to 2mins short runs. 

 

I have data and knowledge now to experiment with thanks all. 

Thanks Fahim! I also have a small (5"; 127 mm) Maksutov Cassegrain and I too really like using it to get the best results I can out of a small aperture. The Small Bore Challenge threads are great - I will be posting there ,I hope, from September-December when I am reunited with that scope in Europe. Keep honing your skills there and maybe treat yourself to a larger scope one day!


Edited by Lacaille, 19 July 2018 - 05:11 PM.



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